Tropical Depression 9 could become season’s first hurricane, threatening Gulf Coast

The National Hurricane Center has officially labeled Invest 92L as Tropical Depression Nine, and it is likely to become our first hurricane of the season before making landfall, probably along the central Gulf Coast, sometime between Friday night and Saturday morning.

We have been monitoring this area for days, and over the last 24 to 36 hours, we have noticed that the low-pressure area that developed on Monday has become better organized. Hurricane hunters, specifically the NOAA Gulfstream jet, have been flying around the system and will continue to investigate it throughout the evening. Hurricane hunters from the Air Force Reserve's 53rd Weather Reconnaissance Squadron are expected to investigate the system on Wednesday morning.

The first advisory issued by the National Hurricane Center at 5 p.m. on Tuesday indicates that the system has maximum sustained winds of 35 mph and is moving east at around 5 mph. No coastal watches or warnings are currently in effect, but this will likely change as early as Wednesday evening across parts of the Gulf Coast.

First, some areas can expect tropical storm watches, which could be upgraded to warnings on Thursday or Friday. The tropical depression is expected to continue moving east-northeast during the next couple of days. By Friday, the system should start turning northeast as it approaches the northern Gulf Coast of the United States.

In the short term, between Tuesday evening and Thursday morning, the system is expected to move at less than 10 mph. Once the system makes that northward turn, it should start picking up speed as steering winds influence it.

Sea surface temperatures are running around 1.8°F above average for this time of year across the Gulf. There is not only plenty of warm water, but it also extends very deep. Therefore, there is plenty of fuel available for the system to intensify. The main factor working against this system is strong wind shear dropping from the continental United States toward the Southeast. So, even though the system has plenty of time and warm water to intensify, wind shear could definitely limit its development.

What are the possible impacts to Florida?

Florida will continue to receive heavy rain through much of this week. Remember, the rain we have been receiving this week has mainly been due to local effects across the southern half of Florida, as well as a stationary frontal boundary across Central Florida, North Florida, and the Panhandle. This frontal boundary will continue to meander around the region at least through Thursday, so expect periods of heavy rain that could lead to flash flooding in some areas.

The Weather Prediction Center continues to place portions of Florida, especially areas from Central Florida through the Lake Okeechobee region, under a marginal risk for flash flooding. By Friday into Saturday, the Weather Prediction Center highlights the western portion of the Panhandle, from areas just west and south of Tallahassee through Pensacola, under a slight risk for flash flooding due to the approaching tropical system.

Florida needs to closely monitor any shift in the track toward the east, as a closer path could potentially bring rounds of heavy rain across the Peninsula. As of Tuesday, the forecast track is far enough west for much of Florida to receive only sporadic rain bands associated with the system. If the system's path shifts farther east, however, we could see more persistent rainfall and a higher threat of tornadoes.

The National Hurricane Center reports rainfall totals of around 4 to 6 inches from Tropical Depression Nine across the western Panhandle. Parts of the Tampa Bay area could also receive around 4 inches of rain.

We will continue to monitor any changes closely and bring you frequent updates throughout the week.